06 January 2008

Daylight Savings and the Energy Crisis

On this date in 1974, the United States enacted year-round daylight savings time.

The concept of daylight savings time has always been a strange one to me. No matter what number one attaches to a particular time of day, it has no effect on the number of hours of sunlight, but it can have a huge effect on human activities, mostly because the majority of us working folks are on a relatively strict work schedule. Nine to five may be a bit of a cliche, but it still remains the most common work day, at least in the United States. There are a lot of interesting consequences to the difference between it being light and dark outside when that 5-o'clock bell rings.

Studies have shown a reduction in both crime and traffic accidents during daylight savings time. It makes a certain amount of sense when you think about it. If the average person is home and (relatively) secure by the time it gets dark, there is both less driving in the dark and less walking in the dark through what might be suspicious territory.

Daylight savings also has a huge effect on energy use, and that is the effect that brings up today's blog post. Because of our enforced work schedules, people tend to go to sleep at about the same time regardless of the timing of sunlight. So, the energy used on electric lighting in the home tends to be less during daylight savings time because there are fewer hours between returning home from work and turning almost everything off to go to sleep. If gas happens to be in low supply, this little difference can be important.

In 1974, gas was, to say the least, in low supply. The energy crisis was in full stride, after OPEC decided to use the West's oil dependence as a weapon to punish us for our support of Israel in the fourth Arab-Israeli War. Price controls and rationing were already well in place when the New Year came around and the decision was made to extend daylight savings to further reduce energy use. As it turned out, the problems had reached their worst point and were starting to abate. It would be two months later, on March 17, that OPEC dropped the embargo and things started to normalize. Still, for those of us who complain about $4 gas and marvel at $100/barrel oil, it is worth remembering a time when we not only had to wait our turn to get gas, but also actually changed our clocks to save it.